1. Field of the Invention
The present invention relates to a method of improving shunt detection on railroad tracks and to a railroad highway crossing signal electronic assembly, and more particularly, but not by way of limitation, to a railroad highway crossing signal electronic assembly that improves train detection on rails with poor shunting conditions.
2. Description of the Related Art
Grade-crossing signals and gate arms can be actuated by a variety of track circuits. A traditional relay circuit has often been used for grade-crossing signals and gate arms.
When the circuit detects the presence of a train, it actuates circuits that cause grade-crossing signals to begin flashing and cause gates to be lowered if train exists in the crossing.
Grade crossing predictor circuits are able to determine a distance from the train to the crossing and can determine whether the train is approaching the crossing or moving away from the crossing. This ability allows a controller to activate a warning system with a warning time prior to the train reaching the crossing.
Some prior circuits employ tuned shunts at either end of an approach area to a crossing and work by transmitting a signal through the rails and shunts and sensing an inductance (or impedance) of the circuit formed by the track rails and shunts.
When a train approaches a crossing, the train's axles and wheels create a short circuit between the pair of rails, which towers the total apparent inductance.
By monitoring the inductance or impedance changes, the location of the train can be determined so that a warning system can be activated.
Unfortunately, grade crossing circuits do not work in all circumstances. For example, grade crossing circuits may not work, or may not work reliably, with poor shunting conditions.
Poor shunting conditions may be caused by low traffic on the rails, which may in turn cause rusts on the rails.
Poor shunting conditions may also be caused by light weight cars on the rails.
Poor shunting conditions may also be caused by vegetation, such as weeds, growing around the tracks, which prevents an electrical connection between the wheels and the tracks.
Based on the foregoing, it is desirable to provide a railroad highway crossing signal electronic assembly with high current sparks to jump gaps between the wheels and the track rails to overcome poor shunting conditions.
It is further desirable to provide an improved railroad highway crossing signal electronic assembly that can manage a C-style circuit.
It is further desirable to make a more cost effective railroad highway crossing signal electronic assembly that uses a single integrated unit to manage train detection and to activate warning lights and gates.